Remap item categories to have integer distances of 1
The mirt package's estimation setup requires that all item responses have spaces
equal to 1 (e.g., a Likert scale scored from 1 through 5). In the event that categories
are missing the categories must be re-coded. This function is automatically called by
the package estimation functions (e.g., mirt), however for convince this
function has been extracted for users to better understand the remapping consequences.
remap.distance(data, message = TRUE)
data |
the response data to remap as a data.frame or matrix |
message |
logical; print message information pertaining to which items were remapped? |
Phil Chalmers rphilip.chalmers@gmail.com
Chalmers, R., P. (2012). mirt: A Multidimensional Item Response Theory Package for the R Environment. Journal of Statistical Software, 48(6), 1-29. doi: 10.18637/jss.v048.i06
# category 2 for item 1 missing dat <- Science dat[,1] <- ifelse(Science[,1] == 2, 1, Science[,1]) apply(dat, 2, table) # mirt() automatically remaps categories mod <- mirt(dat, 1) coef(mod, simplify=TRUE) # this is the transformed data used by mirt() remap_dat <- remap.distance(dat) apply(remap_dat, 2, table)
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